The present invention relates to a machine for spectacle lens for forming a hole to mount a frame on a spectacle lens when a rimless spectacle frame is mounted on the spectacle lens.
A rimless spectacle frame, i.e. a so-called two-point frame is used as a spectacle lens frame from the viewpoints of design and lightweight structure.
As shown in FIG. 5, a two-point frame 1 is designed in such a manner that left and right spectacle lenses 2 and 2 are directly connected by a bridge 3, and one end of a temple 4 is directly fixed on the spectacle lens 2. The fixing of the bridge 3 on the spectacle lens 2 and the fixing of the temple 4 on the spectacle lens 2 are executed via a screw 5 or a pin, which penetrates the spectacle lens 2.
Therefore, for the purpose of attaching the two-point frame 1, a hole where the screw or the pin is penetrating is formed on the spectacle lens 2.
FIG. 6 is a perspective view of a conventional type machine 7 for spectacle lens for forming a hole on the spectacle lens 2.
The machine 7 for spectacle lens comprises a lens holding table 9 and a drill supporting unit 11 mounted on a base 8.
The lens holding table 9 has a Y-axis table 12 to move in a direction (Y-axis direction) to come closer to or to be separated away from the drill supporting unit 11, and an X-axis table 13 to move in a direction (X-axis direction) perpendicularly crossing the Y-axis. When a Y-axis handle 14 is rotated in a normal or reverse direction, the Y-axis table 12 comes closer to or is separated away from the drill supporting unit 11. When an X-axis handle 15 is rotated in a normal or reverse direction, the X-axis table 13 is moved to the left or to the right.
On an upper surface of the X-axis table 13, a lens holding unit 16 is provided.
The lens holding unit 16 comprises a reference plane 17 and a stopper-roller 18, which is disposed at a certain distance from the reference plane 17. The spectacle lens 2 is pressed to the reference plane 17 and the spectacle lens 2 is also pressed to the stopper-roller 18. As a result, positioning of the spectacle lens 2 is performed and its posture is determined.
It is so designed that the spectacle lens 2 is fixed on the X-axis table 13 by a T-shaped spectacle presser 19. The spectacle presser 19 is removably fixed by screws. In the figure, reference numeral 20 denotes a reference line marked on the spectacle lens 2.
The drill supporting unit 11 is provided with a slide guide unit 21, which can be tilted in left and right directions around its lower end. A slider 22 is mounted on the slide guide unit 21 so that the slider 22 can be moved in a vertical direction (Z-axis direction). The slider 22 can be moved in a vertical direction by operating a Z-axis handle 23.
A drill 24 for drilling a hole is attached on the slider 22, and the drill 24 is rotated by an electric motor (not shown).
Now, description will be given on a case where holes are drilled on the spectacle lens 2 in the conventional type machine 7 for spectacle lens.
First, the spectacle lens 2 is set on the lens holding unit 16. Then, the spectacle lens 2 is moved to a machining position and a hole is drilled.
Under the condition that the spectacle presser 19 is taken off, the left and the right spectacle lenses 2 to be machined are placed on the lens holding unit 16, and positioning and posture alignment are performed on each of the spectacle lenses 2.
To perform the positioning and the posture alignment, an upper edge of the spectacle lens 2 is pressed to the reference plane 17, and the spectacle lens 2 is further pressed to the stopper-roller 18. For the tilting of the spectacle lens 2, the reference line 20 is utilized. When the positioning and the posture alignment have been completed, the spectacle presser 19 is mounted, and the spectacle lens 2 is fixed on the lens holding unit 16.
When the upper surface of the spectacle lens 2 is curved, the slide guide unit 21 is tilted and adjustment is made so that the drill 24 is directed perpendicularly to the surface of the spectacle lens 2. The Y-axis handle 14 and the X-axis handle 15 are rotated, and the Y-axis table 12 and the X-axis table 13 are moved to the hole drilling position. While the drill 24 is being rotated, the drill 24 is moved down by operating the Z-axis handle 23, and a hole is drilled on the spectacle lens 2.
Depending on the type of the spectacle frame, the spectacle lens 2 must be mounted by tilting the spectacle lens 2 because of its design. For instance, under the condition that spectacles are put on, each of the spectacle lenses may be tilted upward from the center to the edge. When such type of spectacle frame is used, the spectacle lenses 2 must be tilted to be symmetrical to left and right when the positioning of the spectacle lens 2 is performed on the lens holding unit 16.
In the conventional machine 7 for spectacle lens as described above, the machine has positioning function in Y-axis and X-axis directions of the spectacle lens 2 but has no positioning function for tilting. Therefore, an operator must tilt the spectacle lens 2 manually. However, how far the spectacle lens 2 should be tilted depends on the sense and the skill of the operator. The accuracy in finishing depends on the skill of the operator. In some cases, the balance between left and right may be lost.